Study shows accuracy of 90-minute COVID-19 test

Consumer DNA testing technology repurposed to rapidly diagnose COVID-19 has shown over 94 per cent sensitivity and 100 per cent specificity.

DnaNudge in-store DNA testing service set to testing for Covid-19 (Image: DnaNudge)

DnaNudge’s consumer DNA testing device was re-engineered at the outset of the pandemic to provide a rapid, lab-free reverse transcription polymerase chain reaction (RT-PCR) COVID-19 testing system. A study led by scientists from Imperial College London and supported by the National Institute for Health Research has confirmed the system’s efficacy.

In the research, the high-speed CovidNudge tests, which do not require a laboratory and can be performed in cartridges smaller than a mobile phone, were used on 386 NHS staff and patients. The Lab-in-Cartridge rapid testing device was shown to have a high level of accuracy and produced very few false negatives and no false positives. The study, conducted during the peak of COVID-19, is detailed in The Lancet Microbe.

The CovidNudge test is currently being used across eight London hospitals and is due to be rolled out nationally. Data continues to be gathered from the testing device for continual assessment.

To perform the test, a paediatric-sized nose swab from a patient is inserted into the device, which then looks for traces of genetic material belonging to the SARS-CoV-2 virus, which causes COVID-19.

A result is available within 90 minutes, compared to conventional COVID-19 testing which delivers a result in 24 hours.  The test is now being developed for assessing simultaneously Flu-A, Flu-B, and RSV (Respiratory Syncytial Virus) as well as COVID19.

In a statement, Prof. Graham Cooke, lead author of the study from the Department of Infectious Disease at Imperial said: “These results suggest the test, which can be performed at a patient’s bedside without the need to handle any sample material, has comparable accuracy to standard laboratory testing.

"Many tests involve a trade-off between speed and accuracy, but this test manages to achieve both. Developing an effective bedside test in under three months has been an incredible collaboration between teams of engineers, clinicians and virologists.”

The device was used on 280 NHS staff members with suspected COVID-19, 15 patients in A&E with suspected COVID-19, and 91 hospital in-patients (some of whom were not displaying COVID-19 symptoms). The samples from all individuals in the study were analysed on the CovidNudge rapid-testing device and standard hospital laboratory equipment.

The percentage of those found to be positive for COVID-19 was 18 per cent. The results showed 67 samples tested positive on the CovidNudge test, compared with 71 positive results against a range of NHS standard laboratory machines, which represents the value of 94 per cent sensitivity.

Regius Professor Chris Toumazou,  CEO and co-founder of DnaNudge and founder of the Institute of Biomedical Engineering at Imperial, said: “The DnaNudge test was developed as a lab-free, on-the-spot consumer service that can be delivered at scale, so we clearly believe it offers very significant potential in terms of mass population testing during the COVID-19 pandemic. The platform is well suited to testing in primary care and community settings with potential for use in non-healthcare settings such as care homes, schools, transport hubs, offices, and, to help bring the arts back, in theatres and venues. However, further studies of real-world effectiveness in non-clinical settings would be required prior to widespread deployment.”

The UK government recently placed an order for 5.8 million of the testing kits and Imperial spin-out DnaNudge has partnered with Arizona-based Benchmark Electronics for volume production of its test kits.